Android Camera LED light goes to Off after 2 seconds?

Question

I am using the camera flash light in my application, I was done coding for that, it's working on/off the light. but after 2 seconds it goes to off. If I press the on button again it was giving force close. This is the code i am using for this, please help me.

I want this like if user presses the on button light On, upto user press Off button.

private void processOffClick()  {

    //togglebutton.setButtonDrawable(R.drawable.offbutton);
    System.out.println("in off state");
    if( cam != null ){
        cam.stopPreview();
        cam.release();
    }
}
private void processOnClick()  {

    //togglebutton.setButtonDrawable(R.drawable.onbutton);
    System.out.println("in on state");       
    cam = Camera.open();     
    Parameters params = cam.getParameters();
    params.setFlashMode(Parameters.FLASH_MODE_ON);
    cam.setParameters(params);

    cam.startPreview();
    cam.autoFocus(new AutoFocusCallback() {
        public void onAutoFocus(boolean success, Camera camera) {
        }
    });      
}

In which device you tested the code ?.`if i press again on button it was giving force close` -- post the logat. — Kartik Domadiya, Nov 14 '11 at 07:18
Well I also face the same issue. You can refer my question : http://stackoverflow.com/questions/6939816/turn-on-off-camera-led-flash-light-in-samsung-galaxy-ace-2-2-1-galaxy-tab.. It has got more than 3.5k views but still no answer. — Kartik Domadiya, Nov 14 '11 at 08:06
I'm not sure about that but you should try it, When you are telling the device to turn on the flash it turns it for a certain amount of time that I'm not sure if you can set it or not. Anyways, try to put the lines Parameters params = cam.getParameters(); params.setFlashMode(Parameters.FLASH_MODE_ON); cam.setParameters(params); in processOfClick and check it out, it might cancel the error — Baruch, Nov 14 '11 at 08:07
@Baruch u want place code in processOnClick or processOffClick, please correct u r comment. — NagarjunaReddy, Nov 14 '11 at 08:34
@NagarjunaReddy : Some of the devices does not support `FLASH_MODE_TORCH` because that mode is not available in that device. Your phone Samsung Galaxy Ace doesnot have `FLASH_MODE_TORCH` — Kartik Domadiya, Nov 15 '11 at 10:36

score 1 · Accepted Answer · edited Nov 15 '11 at 10:20

put the lines:

Parameters params = cam.getParameters();
params.setFlashMode(Parameters.FLASH_MODE_ON);
cam.setParameters(params);

in processOffClick instead of putting it in processOnClick like that:

boolean clicked = false;
private void processOffClick()  {

  //togglebutton.setButtonDrawable(R.drawable.offbutton);
  clicked = false;
  System.out.println("in off state");
  if( cam != null ){
      cam.stopPreview();
      cam.release();
  }
}
private void processOnClick()  {
  clicked = true;
  //togglebutton.setButtonDrawable(R.drawable.onbutton);
  System.out.println("in on state");       
  cam = Camera.open();     
  Parameters params = cam.getParameters();
  params.setFlashMode(Parameters.FLASH_MODE_ON);

  while(clicked)  { 
     cam.setParameters(params);

     cam.startPreview();
        cam.autoFocus(new AutoFocusCallback() {
           public void onAutoFocus(boolean success, Camera camera) {
        }
     });
  } 
}

It might work, i didn't check the code

I added a while loop so it would hold the flash and the focus until its unclicked.

light working ,but here the screen was not able to display (buttons are not displaying ).i think it goes to camera preview, i want only light. — NagarjunaReddy, Nov 15 '11 at 04:34
You#re starting the preview of the camera over and over and over again oO ? This seems rather odd - without stopping it in between. My point being, that it doesn't seem very "healthy" to torture the camera like this :O ? — AgentKnopf, Dec 19 '12 at 18:40

score 1 · Answer 2 · answered Nov 15 '11 at 10:23

1

My experience says, that flash mode ought to be "TORCH" ( if supported ) and it is started only when you start preview. However, cameras behave very differently on different devices and not always as advertised in their capabilities descrioptors

answered Nov 15 '11 at 10:23

Konstantin Pribluda

12,329
1
30
35

NagarjunaReddy · Answer 3 · 2012-10-20T09:39:56.000

1.Turn on

camera = Camera.open();
Parameters p = camera.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_TORCH);
camera.setParameters(p);
camera.startPreview();

2. Turn off

camera = Camera.open();
Parameters p = camera.getParameters();
p.setFlashMode(Parameters.FLASH_MODE_OFF);
camera.setParameters(p);
camera.stopPreview();

And, put following permission on AndroidManifest.xml.

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />

see this one http://www.mkyong.com/android/how-to-turn-onoff-camera-ledflashlight-in-android/

Android Camera LED light goes to Off after 2 seconds?

3 Answers3